In creating a version of 'html2xhtml.xsl' that supported XHTML 1.1, I found the one thing I couldn't easily fix was the 'lang' attribute.
The approach that I'd like to use is to just redirect all the call-templates to 'xml.language.attribute' rather than 'language.attribute'.
Of course I'd like the template to be in the common/l10n.xsl stylesheet so that it's part of distribution.
Closing, since an xml.language.attribute template has been added to l10n.xsl.
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